Distribution. Shady hillsides on the borders of the forest and often in the neighborhood of streams; coast mountains of California from Mendocino County to the valley of the San Luis Rey River, San Diego County; of its largest size northward, and in the Redwood-forests of the Santa Cruz Mountains; southward often a low shrub, frequently flowering on the wind-swept shores of the ocean when only 1°—2° high.
3. [Ceanothus spinosus] Nutt. Lilac.
Leaves elliptic to oblong, full and rounded, apiculate or often slightly emarginate or gradually narrowed and pointed or rarely 3-lobed at apex, and rounded or cuneate at base, when they unfold villose-pubescent below along the stout midrib and obscure primary veins, soon glabrous, coriaceous, usually about 1′ long and ½′ wide; petioles stout, ⅙′—⅓′ in length, at first villose, becoming nearly glabrous; leaves on vigorous shoots sometimes ovate, conspicuously 3-nerved, irregularly serrate with incurved apiculate teeth, or coarsely dentate, and often 1½′ long and ⅝′ wide; stipules minute, acute. Flowers light or dark blue, very fragrant, opening from March until May, in lax corymbs from the axils of acute pubescent red caducous bracts on upper leafy branchlets of the year, the whole inflorescence forming an open thyrsus often 5′—6′ long and 3′—4′ thick, leafless toward the apex. Fruit depressed, obscurely lobed, crestless, black, ¼′—⅓′ in diameter.
A tree, 18°—20° high, with a trunk 5′—6′ in diameter, upright branches forming a narrow open head, and slender divaricate angled branchlets pubescent or puberulous when they first appear, soon glabrous, bright green, ultimately reddish brown, frequently terminating in sharp leafless thorn-like points; more often shrubby. Bark of the trunk thin, red-brown, roughened by small closely appressed scales.
Distribution. California, common in mountain cañons near the coast of Santa Barbara, Ventura, and Los Angeles Counties; often forming a dense undergrowth in the forest, which it enlivens for many weeks in early spring by its large clusters of bright blue flowers.
6. COLUBRINA Brong.
Trees or shrubs, with terete branches and scaly buds. Leaves alternate, petiolate, pinnately veined or triple-veined from the base, often ferrugineo-tomentose on the lower surface, persistent. Flowers axillary, in contracted few-flowered cymes or fascicles, yellow or greenish yellow; calyx-tube hemispheric, persistent, 5-lobed, the lobes spreading, triangular-ovate, keeled on the inner surface, deciduous by a circumscissile line; disk fleshy, annular, 5-angled or indistinctly 5 or 10-lobed; petals 5 yellow or white, inserted under the margin of the disk, shorter than the lobes of the calyx, cucullate, unguiculate, infolding the stamens; stamens 5, opposite to and inserted with the petals; filaments incurved; anthers ovoid; ovary surrounded by and confluent with the disk, 3-celled, subglobose, contracted into a slender 3-lobed style, the obtuse lobes stigmatic on the inner face; ovule erect, from the base of the cell. Fruit subglobose, 3-lobed, the outer coat thin and septicidally dehiscent into 3 1-seeded crustaceous nutlets 2-valved at apex. Seeds erect, broad-obovoid, compressed, 3-angled; seed-coat coriaceous, smooth and shining; embryo axile in thick fleshy albumen; cotyledons orbicular, flat or incurved, thin or fleshy.
Colubrina with about a dozen species is confined to the tropics, with the largest number of species in the New World. Of the four species found within the territory of the United States three are arborescent.
The generic name is from coluber, a serpent, probably on account of the peculiar twisting of the deep furrows on the stems of some of the species.